The following example demonstrates how to create a custom ValidationRule and apply it to a column's binding to provide binding-level validation.

The implementation for the YearValidationRule is provided below.

XAML
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<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"

     xmlns:local="clr-namespace:Xceed.Wpf.Documentation">

  <Grid.Resources>

     <xcdg:DataGridCollectionViewSource x:Key="cvs_composers"

                                        Source="{Binding Source={x:Static Application.Current}, 

                                                         Path=Composers}"/>

  </Grid.Resources>

 

  <xcdg:DataGridControl ItemsSource="{Binding Source={StaticResource cvs_composers}}"

                        UpdateSourceTrigger="RowEndingEdit">

     <xcdg:DataGridControl.Columns> 

       <xcdg:Column FieldName="BirthYear">

          <xcdg:Column.DisplayMemberBindingInfo>

             <xcdg:DataGridBindingInfo Path="BirthYear">

                <xcdg:DataGridBindingInfo.ValidationRules>

                   <local:YearValidationRule />

                </xcdg:DataGridBindingInfo.ValidationRules>

             </xcdg:DataGridBindingInfo>

          </xcdg:Column.DisplayMemberBindingInfo>

       </xcdg:Column>

       <xcdg:Column FieldName="DeathYear">

          <xcdg:Column.DisplayMemberBindingInfo>

             <xcdg:DataGridBindingInfo Path="DeathYear">

                <xcdg:DataGridBindingInfo.ValidationRules>

                   <local:YearValidationRule />

                </xcdg:DataGridBindingInfo.ValidationRules>

             </xcdg:DataGridBindingInfo>

          </xcdg:Column.DisplayMemberBindingInfo>

       </xcdg:Column>      

    </xcdg:DataGridControl.Columns>

  </xcdg:DataGridControl>

</Grid>

Implementation of the YearValidationRule validation rule.

VB.NET
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Imports System

Imports System.Windows.Controls

Imports System.Globalization

Namespace Xceed.Wpf.Documentation

  Public Class YearValidationRule

               Inherits ValidationRule

    Public Overrides Function Validate( ByVal value As Object, _

                                        ByVal cultureInfo As CultureInfo ) As ValidationResult

      Dim year As Integer = CInt( value )

      If year > DateTime.Now.Year Then

        Return New ValidationResult( False, "Chosen year cannot be greater than this year." )

      End If

      Return ValidationResult.ValidResult

    End Function

  End Class

End Namespace
C#
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using System;

using System.Windows.Controls;

using System.Globalization;

namespace Xceed.Wpf.Documentation

{

 public class YearValidationRule : ValidationRule

 {

   public override ValidationResult Validate( object value, CultureInfo cultureInfo )

   {

     int year = ( int )value;

     if( year > DateTime.Now.Year )

       return new ValidationResult( false, "Chosen year cannot be greater than this year." );

     return ValidationResult.ValidResult;

   }

 }

}